This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-291296, filed Sep. 25, 2000, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a perpendicular magnetic recording head and a perpendicular magnetic recording apparatus.
2. Description of the Related Art
In a computer field, a magnetic disk apparatus has been much utilized as a randomly accessible external storage having a large capacity. With expanding utilization, for the magnetic disk apparatus, there has been an increasing demand for enhancement of a storage capacity and recording density.
As a method of enhancing the recording density of the magnetic disk apparatus, perpendicular magnetic recording has been proposed. In the perpendicular magnetic recording, as compared with longitudinal magnetic recording, a demagnetizing field in a magnetization transition can remarkably be reduced, a magnetization transition width can be narrowed, and high-density recording is realized. Moreover, in order to raise recording and reproducing efficiencies in the perpendicular magnetic recording, and form a steeper magnetization transition, a magnetic disk of a perpendicular double-layer film medium having a soft magnetic backing layer disposed under a perpendicular magnetic recording layer has been proposed.
A conventional perpendicular magnetic recording head having the following structure has heretofore been used for the perpendicular double-layer film medium formed by stacking the soft magnetic backing layer, having a thickness of 50 nm to several hundreds of nanometers, and the perpendicular magnetic recording layer. The structure includes a recording main pole (trailing pole), an auxiliary pole (leading pole) disposed as a return yoke at a gap from the recording main pole, and an exciting coil acting on these poles. In the perpendicular magnetic recording head, a magnetic field generated by the exciting coil is passed through the recording main pole, soft magnetic backing layer and auxiliary pole to form a closed magnetic path, a magnetic flux can be concentrated on the recording main pole, and recording efficiency can therefore be enhanced. In the conventional perpendicular magnetic recording head, in order to prevent a strong magnetic field from being generated under the auxiliary pole, an area of the air-bearing surface of the auxiliary pole is set to be larger than that of the main pole, and a gap between the main pole and the auxiliary pole is set to be as large as several micrometers.
However, in the conventional perpendicular magnetic recording head, under a high track density of a track pitch of 1 xcexcm or less with enhancement of the recording density, the magnetic field generated under the auxiliary pole extends to adjacent tracks. As a result, it is seen that recorded magnetization in the adjacent track is disadvantageously disturbed by repeated recording in a certain track.
In Jap. Pat. Appln. KOKAI Publication No. 11-66503, it is described that the perpendicular magnetic recording head having a gap length between the recording main pole and the auxiliary pole in a range of 0.2 to 0.5 xcexcm is used in recording with respect to the perpendicular double-layer film medium of the stack of the soft magnetic backing layer having a thickness of about 10 to 50 nm and the magnetic recording layer having perpendicular magnetic anisotropy. This publication aims at improvement in resolution of perpendicular magnetic recording and overwrite characteristics. However, in the publication, a low track density is presumed, influences onto the adjacent tracks is not considered, and therefore this publication cannot be applied to design a perpendicular magnetic recording head used under a high recording density.
An object of the present invention is to provide a perpendicular magnetic recording head and perpendicular magnetic recording apparatus in which an adverse effect onto adjacent tracks can be inhibited during perpendicular magnetic recording with respect to a perpendicular double-layer medium.
According to one aspect of the prevent invention, there is provided a perpendicular magnetic recording head performing magnetic recording under a condition that a recording track pitch as a total of a recording track width and a guard-band width between the recording tracks is set to be 1 xcexcm or less, the head comprising: a recording main pole; an auxiliary pole disposed at a gap from the recording main pole; and an exciting coil, a gap length between the recording main pole and the auxiliary pole being five or less times the guard-band width between the recording tracks.
According to another aspect of the present invention, there is provided a perpendicular magnetic recording apparatus comprising; a perpendicular double-layer film medium having a stacked structure of a soft magnetic backing layer and a perpendicular magnetic recording layer in which magnetic recording is performed under a condition that a recording track pitch as a total of a recording track width and a guard-band width between recording tracks is set to be 1 xcexcm or less; and a perpendicular magnetic recording head comprising a recording main pole, an auxiliary pole disposed at a gap having a length of five or less times the guard-band width with respect to the recording main pole, and an exciting coil.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.